In a wireless communication apparatus such as a portable telephone device, power loss is caused by mismatching between an input impedance of the antenna and an output impedance of the power amplifier. There is a method for reducing the power loss. According to the method, a variable impedance matching circuit is provided between the antenna and a radio, mismatching is detected by monitoring power being released from the antenna, and matching is automatically achieved between the input impedance of the antenna and the output impedance of the radio.
Meanwhile, there are cases where TPC (Transmission Power Control) is performed to maintain a preferred communication state by making the gain of the power amplifier variable, and changing transmission power in accordance with variations in the communication state. Where TPC is performed, example causes of variations in the power released from the antenna include the following three factors.    (1) A change in the state of the variable impedance matching circuit (hereinafter also referred to simply as a state change).    (2) A change in the gain of the power amplifier (hereinafter also referred to simply as a gain change).    (3) A change in the environment surrounding the wireless communication apparatus (hereinafter also referred to simply as an environmental change).
Where TPC is performed, it is difficult to determine which change factor has caused a variation in the power released from the antenna. If a state change or an environmental change is not distinguished from a gain change in a control operation, power consumption might increase due to an unnecessary matching operation, or an incorrect operation might be performed in automatic impedance matching.